As is known in the art, a cursor on a computer screen can be used to input commands into a computer. The cursor contains a hot point that indicates the location of the cursor itself. A user can input commands to move the cursor on the screen, thus moving the hot point, by using keyboard arrow keys or a pointing device such as a mouse or trackball.
By moving the cursor and placing the hot point on a particular portion of the screen, commands can be entered into the computer. For example, a computer may have a software program which includes pull-down menus. By placing the hot point of the cursor on a pull-down menu and actuating or "clicking" a switch or button, a menu is displayed on the screen from which a user may enter commands. Similarly, by placing the hot point of the cursor on an icon, file name, menu selection, or other object on the screen and clicking the button, a command can be entered to open or act upon a file or application program that is represented by the icon, file name, menu selection or other object. This method of command selection is commonly known as "point and click," and is commonly performed using computer pointing devices such as mice or trackballs. Overall, the point and click method of command selection allows users to more easily operate computers.
Often, pull-down menu selections are placed in a menu bar in a narrow horizontal row across the screen. If a user wishes to move from one menu selection to another, the user must navigate the hot point of the cursor horizontally within this row. Once the user navigates the cursor to the desired menu selection, a list of options is often displayed in a column running vertically on the computer screen. A user must then navigate the hot point of the cursor through this column if the user wishes to move from option to option. Often, many users, including young and handicapped users, have difficulty in navigating the cursor within narrow rows or columns on the screen. These users often move the mouse or ball of the trackball unevenly, causing the cursor to move waveringly or along arcuate or diagonal paths.
In certain software applications, users desire to move a cursor continuously along horizontal and vertical paths. For example, in a large spreadsheet, a user may wish to move a cursor horizontally along a given row or vertically through a given column, without moving the cursor into adjacent rows or columns. In many drawing or painting programs, a user will often wish to draw straight horizontal or vertical lines, thus requiring the cursor to move along straight horizontal and vertical paths. Overall, many users have difficulty navigating a cursor continuously along straight horizontal or vertical paths, even though such cursor movement is desirable.